1 files changed, 83 insertions, 46 deletions

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index cec0f3ba97f..80b47e8ce03 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -17,7 +17,8 @@
 
     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+    MA 02110-1301 USA.
 */
 
 /* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
@@ -28,6 +29,8 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/device.h>
+#include <linux/notifier.h>
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/init.h>
@@ -37,16 +40,13 @@
 #include <linux/jiffies.h>
 #include <linux/uaccess.h>
 
-static struct i2c_driver i2cdev_driver;
-
 /*
  * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
  * slave (i2c_client) with which messages will be exchanged.  It's coupled
  * with a character special file which is accessed by user mode drivers.
  *
  * The list of i2c_dev structures is parallel to the i2c_adapter lists
- * maintained by the driver model, and is updated using notifications
- * delivered to the i2cdev_driver.
+ * maintained by the driver model, and is updated using bus notifications.
  */
 struct i2c_dev {
 	struct list_head list;
@@ -102,8 +102,8 @@ static void return_i2c_dev(struct i2c_dev *i2c_dev)
 	kfree(i2c_dev);
 }
 
-static ssize_t show_adapter_name(struct device *dev,
-				 struct device_attribute *attr, char *buf)
+static ssize_t name_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
 {
 	struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
 
@@ -111,7 +111,13 @@ static ssize_t show_adapter_name(struct device *dev,
 		return -ENODEV;
 	return sprintf(buf, "%s\n", i2c_dev->adap->name);
 }
-static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
+static DEVICE_ATTR_RO(name);
+
+static struct attribute *i2c_attrs[] = {
+	&dev_attr_name.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(i2c);
 
 /* ------------------------------------------------------------------------- */
 
@@ -148,7 +154,7 @@ static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
 		return -ENOMEM;
 
 	pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
-		iminor(file->f_path.dentry->d_inode), count);
+		iminor(file_inode(file)), count);
 
 	ret = i2c_master_recv(client, tmp, count);
 	if (ret >= 0)
@@ -172,7 +178,7 @@ static ssize_t i2cdev_write(struct file *file, const char __user *buf,
 		return PTR_ERR(tmp);
 
 	pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
-		iminor(file->f_path.dentry->d_inode), count);
+		iminor(file_inode(file)), count);
 
 	ret = i2c_master_send(client, tmp, count);
 	kfree(tmp);
@@ -252,15 +258,10 @@ static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
 	if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 		return -EINVAL;
 
-	rdwr_pa = kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), GFP_KERNEL);
-	if (!rdwr_pa)
-		return -ENOMEM;
-
-	if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
-			   rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
-		kfree(rdwr_pa);
-		return -EFAULT;
-	}
+	rdwr_pa = memdup_user(rdwr_arg.msgs,
+			      rdwr_arg.nmsgs * sizeof(struct i2c_msg));
+	if (IS_ERR(rdwr_pa))
+		return PTR_ERR(rdwr_pa);
 
 	data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 	if (data_ptrs == NULL) {
@@ -270,19 +271,41 @@ static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
 
 	res = 0;
 	for (i = 0; i < rdwr_arg.nmsgs; i++) {
-		/* Limit the size of the message to a sane amount;
-		 * and don't let length change either. */
-		if ((rdwr_pa[i].len > 8192) ||
-		    (rdwr_pa[i].flags & I2C_M_RECV_LEN)) {
+		/* Limit the size of the message to a sane amount */
+		if (rdwr_pa[i].len > 8192) {
 			res = -EINVAL;
 			break;
 		}
+
 		data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 		rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
 		if (IS_ERR(rdwr_pa[i].buf)) {
 			res = PTR_ERR(rdwr_pa[i].buf);
 			break;
 		}
+
+		/*
+		 * If the message length is received from the slave (similar
+		 * to SMBus block read), we must ensure that the buffer will
+		 * be large enough to cope with a message length of
+		 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
+		 * drivers allow. The first byte in the buffer must be
+		 * pre-filled with the number of extra bytes, which must be
+		 * at least one to hold the message length, but can be
+		 * greater (for example to account for a checksum byte at
+		 * the end of the message.)
+		 */
+		if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
+			if (!(rdwr_pa[i].flags & I2C_M_RD) ||
+			    rdwr_pa[i].buf[0] < 1 ||
+			    rdwr_pa[i].len < rdwr_pa[i].buf[0] +
+					     I2C_SMBUS_BLOCK_MAX) {
+				res = -EINVAL;
+				break;
+			}
+
+			rdwr_pa[i].len = rdwr_pa[i].buf[0];
+		}
 	}
 	if (res < 0) {
 		int j;
@@ -491,7 +514,6 @@ static int i2cdev_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 	}
 	snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
-	client->driver = &i2cdev_driver;
 
 	client->adapter = adap;
 	file->private_data = client;
@@ -522,19 +544,18 @@ static const struct file_operations i2cdev_fops = {
 
 /* ------------------------------------------------------------------------- */
 
-/*
- * The legacy "i2cdev_driver" is used primarily to get notifications when
- * I2C adapters are added or removed, so that each one gets an i2c_dev
- * and is thus made available to userspace driver code.
- */
-
 static struct class *i2c_dev_class;
 
-static int i2cdev_attach_adapter(struct i2c_adapter *adap)
+static int i2cdev_attach_adapter(struct device *dev, void *dummy)
 {
+	struct i2c_adapter *adap;
 	struct i2c_dev *i2c_dev;
 	int res;
 
+	if (dev->type != &i2c_adapter_type)
+		return 0;
+	adap = to_i2c_adapter(dev);
+
 	i2c_dev = get_free_i2c_dev(adap);
 	if (IS_ERR(i2c_dev))
 		return PTR_ERR(i2c_dev);
@@ -547,29 +568,28 @@ static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 		res = PTR_ERR(i2c_dev->dev);
 		goto error;
 	}
-	res = device_create_file(i2c_dev->dev, &dev_attr_name);
-	if (res)
-		goto error_destroy;
 
 	pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 		 adap->name, adap->nr);
 	return 0;
-error_destroy:
-	device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 error:
 	return_i2c_dev(i2c_dev);
 	return res;
 }
 
-static int i2cdev_detach_adapter(struct i2c_adapter *adap)
+static int i2cdev_detach_adapter(struct device *dev, void *dummy)
 {
+	struct i2c_adapter *adap;
 	struct i2c_dev *i2c_dev;
 
+	if (dev->type != &i2c_adapter_type)
+		return 0;
+	adap = to_i2c_adapter(dev);
+
 	i2c_dev = i2c_dev_get_by_minor(adap->nr);
 	if (!i2c_dev) /* attach_adapter must have failed */
 		return 0;
 
-	device_remove_file(i2c_dev->dev, &dev_attr_name);
 	return_i2c_dev(i2c_dev);
 	device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 
@@ -577,12 +597,23 @@ static int i2cdev_detach_adapter(struct i2c_adapter *adap)
 	return 0;
 }
 
-static struct i2c_driver i2cdev_driver = {
-	.driver = {
-		.name	= "dev_driver",
-	},
-	.attach_adapter	= i2cdev_attach_adapter,
-	.detach_adapter	= i2cdev_detach_adapter,
+static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
+			 void *data)
+{
+	struct device *dev = data;
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		return i2cdev_attach_adapter(dev, NULL);
+	case BUS_NOTIFY_DEL_DEVICE:
+		return i2cdev_detach_adapter(dev, NULL);
+	}
+
+	return 0;
+}
+
+static struct notifier_block i2cdev_notifier = {
+	.notifier_call = i2cdev_notifier_call,
 };
 
 /* ------------------------------------------------------------------------- */
@@ -606,11 +637,16 @@ static int __init i2c_dev_init(void)
 		res = PTR_ERR(i2c_dev_class);
 		goto out_unreg_chrdev;
 	}
+	i2c_dev_class->dev_groups = i2c_groups;
 
-	res = i2c_add_driver(&i2cdev_driver);
+	/* Keep track of adapters which will be added or removed later */
+	res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
 	if (res)
 		goto out_unreg_class;
 
+	/* Bind to already existing adapters right away */
+	i2c_for_each_dev(NULL, i2cdev_attach_adapter);
+
 	return 0;
 
 out_unreg_class:
@@ -624,7 +660,8 @@ out:
 
 static void __exit i2c_dev_exit(void)
 {
-	i2c_del_driver(&i2cdev_driver);
+	bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
+	i2c_for_each_dev(NULL, i2cdev_detach_adapter);
 	class_destroy(i2c_dev_class);
 	unregister_chrdev(I2C_MAJOR, "i2c");
 }